1. Field of the Invention
This invention relates in general to systems for measuring range and range rate of distant objects. In particular, the system relates to the measurement of range and range rate where the range is a relatively short distance from the measuring point to the object. Still more particularly, the invention relates to a range and range rate system for use with orbiting vehicles during docking and closing maneuvers.
2. Description of the Prior Art
Two common methods have existed for measuring range and range rate of a distant object. These two methods use radar and laser devices. Radar devices have a limited minimum range due to the relatively long time duration of transmitted pulses used to measure range.
Laser devices have required sophisticated targets on the object the distance of which is to be measured. Measuring range to vulnerable satellite targets may indicate not using radar or prior art laser devices due to the potential damaging effects of the radiation on the targets.